Epistaxis: an update on current management.

Epistaxis is one of the commonest ENT emergencies. Although most patients can be treated within an accident and emergency setting, some are complex and may require specialist intervention. There are multiple risk factors for the development of epistaxis and it can affect any age group, but it is the elderly population with their associated morbidity who often require more intensive treatment and subsequent admission. Treatment strategies have been broadly similar for decades. However, with the evolution of endoscopic technology, new ways of actively managing epistaxis are now available. Recent evidence suggests that this, combined with the use of stepwise management plans, should limit patient complications and the need for admission. This review discusses the various treatment options and integrates the traditional methods with modern techniques.

Treatment of pseudobulbar affect in ALS with dextromethorphan/quinidine: a randomized trial.

BACKGROUND: Patients with ALS commonly exhibit pseudobulbar affect. METHODS: The authors conducted a multicenter, randomized, double-blind, controlled, parallel, three-arm study to test a defined combination of dextromethorphan hydrobromide (DM) and quinidine sulfate (Q) (AVP-923) for the treatment of pseudobulbar affect in ALS. Q inhibits the rapid first-pass metabolism of DM. The effects of AVP-923 (30 mg of DM plus 30 mg of Q) given twice daily for 28 days were compared with those of its components. Patients were evaluated on days 1, 15, and 29. The primary efficacy variable was the change from baseline in the Center for Neurologic Study Lability Scale (CNS-LS) score. Secondary efficacy variables were laughing/crying episode rates and changes in Visual Analog Scales for Quality of Life (QOL) and Relationships (QOR). Efficacy was evaluated in intention-to-treat subjects who were not poor metabolizers of DM (n = 65 for AVP-923, n = 30 for DM, and n = 34 for Q). Safety was assessed in all randomized subjects (n = 140). RESULTS: AVP-923 patients experienced 3.3-point greater improvements in CNS-LS than DM patients (p = 0.001) and 3.7-point greater improvements than Q patients (p < 0.001). AVP-923 patients exhibited lower overall episode rates, improved QOL scores, and improved QOR scores (p < 0.01 for all endpoints). Adverse effects were mostly mild or moderate; treatment-related discontinuation was 24% for AVP-923, 6% for DM, and 8% for Q. CONCLUSIONS: AVP-923 palliates pseudobulbar affect in ALS. Overall benefits of treatment are reflected in fewer episodes of crying and laughing and improvements in overall quality of life and quality of relationships.

Influence of concomitant quinidine administration on dextromethorphan disposition in rats.

High doses of dextromethorphan (DM) have been clinically investigated for the treatment of multiple neuronal disorders including neuropathic pain. Several authors have suggested the concomitant administration of DM and a CYP2D6 reversible inhibitor in order to enhance the exposure of DM and limit the exposure to total dextrorphan (DX). The present study proposes to determine whether or not a single dose of quinidine is sufficient to enhance the plasma concentrations of DM in rats and keep those of DX at a minimal level. Oral doses of DM (50 mg/kg) were administered with increasing dose levels of quinidine (0, 2, 20, and 50 mg/kg) to male Sprague-Dawley rats and blood samples were collected over 24 h. Plasma concentrations of DM and total DX were determined using ESI-LC/MS/MS. Quinidine coadministration resulted in a more than twofold increase in the area under the curve of DM with an ED(50) of approximately 2 mg/kg whereas those of total DX were only increased by 21%. These results support the working hypothesis that a single dose of quinidine may enhance the plasma concentrations of DM relative to those of total DX and may therefore improve the treatment of neuropathic pain.

Clinical efficacy of topical docosanol 10% cream for herpes simplex labialis: A multicenter, randomized, placebo-controlled trial.

BACKGROUND: Recurrent herpes simplex labialis (HSL) occurs in 20% to 40% of the US population. Although the disease is self-limiting in persons with a healthy immune response, patients seek treatment because of the discomfort and visibility of a recurrent lesion. OBJECTIVE: Our purpose was to determine whether docosanol 10% cream (docosanol) is efficacious compared with placebo for the topical treatment of episodes of acute HSL. METHODS: Two identical double-blind, placebo-controlled studies were conducted at a total of 21 sites. Otherwise healthy adults, with documented histories of HSL, were randomized to receive either docosanol or polyethylene glycol placebo and initiated therapy in the prodrome or erythema stage of an episode. Treatment was administered 5 times daily until healing occurred (ie, the crust fell off spontaneously or there was no longer evidence of an active lesion) with twice-daily visits. RESULTS: The median time to healing in the 370 docosanol-treated patients was 4.1 days, 18 hours shorter than observed in the 367 placebo-treated patients (P =.008; 95% confidence interval [CI]: 2, 22). The docosanol group also exhibited reduced times from treatment initiation to (1) cessation of pain and all other symptoms (itching, burning, and/or tingling; P =.002; 95% CI: 3, 16.5); (2) complete healing of classic lesions (P =.023; 95% CI: 1, 24.5); and (3) cessation of the ulcer or soft crust stage of classic lesions (P <.001; 95% CI: 8, 25). Aborted episodes were experienced by 40% of the docosanol recipients versus 34% of placebo recipients (P =.109; 95% CI for odds ratio: 0.95, 1.73). Adverse experiences with docosanol were mild and similar to those with placebo. CONCLUSION: Docosanol applied 5 times daily is safe and effective in the treatment of recurrent HSL. Differences in healing time compared favorably with those reported for the only treatment of HSL that has been approved by the Food and Drug Administration.

The antiviral drug docosanol as a treatment for Kaposi's sarcoma lesions in HIV type 1-infected patients: a pilot clinical study.

Docosanol inhibits a broad spectrum of lipid-enveloped viruses in vitro including HSV-1, HSV-2, VZV, CMV, HHV-6, and HIV-1. These observations led us to conduct a pilot clinical study with docosanol 10% cream as a topical treatment for Kaposi's sarcoma (KS) in HIV-1-infected patients. In this open-label study 28 cutaneous KS lesions in 10 HIV-1-infected patients were treated topically five times daily for 4 weeks with evaluation of lesion characteristics of area, edema, and color. All patients elected to enroll in an extended treatment protocol and continued to treat for up to 35 weeks. Within 28 days, 2 of 10 patients exhibited a partial response based on standardized criteria exhibiting 74 to 83% reductions in total target lesion areas. With extended treatment, a partial response was exhibited in two additional patients where total target lesion area was reduced by 52% in one patient and target lesions in another patient that had been large, swollen, and painful at study initiation were no longer visible. No patient experienced disease progression or signs of visceral disease. The average percent decrease in lesion area for all target lesions was 20% (p < 0.01). A patient's response to therapy appeared to be independent of anti-HIV regimen, HIV viral load, or previous KS treatments. These results suggest that docosanol merits further investigation as a potential topical therapy in the treatment of AIDS-associated Kaposi's sarcoma lesions.

Topical application of docosanol- or stearic acid-containing creams reduces severity of phenol burn wounds in mice.

Because of their reported antiviral and anti-inflammatory activities, cream formulations containing n-docosanol (docosanol) or stearic acid were tested for effects on chemically-induced burns in mice. In this model, injury was induced by painting the abdomens of mice with a chloroform solution of phenol. This was followed by the topical application of test substances 0.5, 3, and 6 h later. Progression of the wounds was assessed by a single evaluator after 8 h, using a numerical score of gross morphology. Docosanol- and stearic acid-containing creams substantially and reproducibly lessened the severity and progression of skin lesions compared to untreated sites with a 76% and 57% reduction in mean lesion scores, respectively. Untreated wounds appeared red and ulcerated; docosanol cream-treated wounds showed only slight erythema.

The anti-herpes simplex virus activity of n-docosanol includes inhibition of the viral entry process.

n-Docosanol-treated cells resist infection by a variety of lipid-enveloped viruses including the herpesviruses. Previous studies of the mechanism of action demonstrated that n-docosanol inhibits an event prior to the expression of intermediate early gene products but subsequent to HSV attachment. The studies reported here indicate that n-docosanol inhibits fusion of the HSV envelope with the plasma membrane. Evidence suggests that antiviral activity requires a time-dependent metabolic conversion of the compound. Cellular resistance to infection declines after removal of the drug with a t1/2 of approximately 3 h. Reduced expression of viral genes in n-docosanol-treated cells was confirmed by a 70% reduction in expression of a reporter gene regulated by a constitutive promoter inserted into the viral genome. Inhibited release in treated cells of virion-associated regulatory proteins--an immediate post entry event--was indicated by a 75% reduction in the expression of beta-galactosidase in target cells carrying a stably transfected lacZ gene under control of an HSV immediate--early promoter. Finally, the fusion-dependent dequenching of a lipophilic fluorescent probe, octadecyl rhodamine B chloride, inserted into the HSV envelope was significantly inhibited in treated cells. Inhibition of fusion between the plasma membrane and the HSV envelope, and the subsequent lack of replicative events, may be the predominant mechanism for the anti-HSV activity of n-docosanol.

Anti-herpes simplex virus activity of n-docosanol correlates with intracellular metabolic conversion of the drug.

The 22-carbon fatty alcohol, n-docosanol, exhibits in vitro antiviral activity against several lipid-enveloped viruses including herpes simplex viruses 1 and 2 by a mechanism that interferes with normal viral entry into target cells. We previously reported that mammalian cells incorporate significant quantities of radiolabeled n-docosanol. Herein, we report that cells extensively metabolize the internalized fatty alcohol. This is evidenced by incorporation of up to 60% of cell-associated radiolabel into phospholipids that copurify with phosphatidylcholine and phosphatidylethanolamine. Analysis by chemical (Vitride) reduction suggests that a significant portion of n-docosanol is oxidized to n-docosanoic acid and then incorporated as an acyl group on polar lipids. A measurable amount of radiolabel, however, is resistant to Vitride reduction, consistent with incorporation of n-docosanol into ether lipids. The rate and extent of metabolic conversion of n-docosanol vary with the cell type and surfactant used to suspend the compound. Furthermore, the anti-HSV activity of n-docosanol is quantitatively proportional to the amount of metabolism observed. These findings suggest that the anti-HSV activity of n-docosanol involves cellular uptake and metabolism of the drug.

Membrane transport of folate compounds.

All eukaryotic cells and some prokaryotes that are unable to synthesize folic acid utilize membrane-associated transport systems for acquisition of the pre-formed vitamin or its coenzyme forms from external sources. These transport systems, in addition to providing folates essential for cell replication, are also important because of their role in the internalization of antifolates such as Methotrexate (MTX) that are used extensively in cancer chemotherapy. Information about the components and mechanism of folate transport systems has been derived, in large part, from studies with Lactobacillus casei and L1210 mouse leukemia cells, which serve as convenient models for prokaryotes and eukaryotes, respectively. L. casei contain a single folate transport system whose Kt value (i.e., concentration for half-maximum rate of uptake) for the preferred substrate folate is in the nanomolar range. The hydrophobic membrane-associated folate transport protein (18 kDa) has been purified to homogeneity and characterized. Expression of this transporter is repressed in cells grown on high concentrations (microM) of folate. L1210 cells contain two separate transport systems for folate compounds: (1) the low affinity system (Kt values for the preferred substrates 5-methyl- and 5-formyltetrahydrofolate and MTX in the microM range); and (2) the high affinity system (Kt for folate in the nM range). Fluorescein and biotin derivatives of MTX and folate, after conversion to N-hydroxysuccinimide esters, can be attached covalently to the transporters. These probes have been used for visualizing the transporters by fluorescence and electron microscopy and for their purification to homogeneity.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiviral activity of 1-docosanol, an inhibitor of lipid-enveloped viruses including herpes simplex.

This article reports that 1-docosanol, a 22-carbon-long saturated alcohol, exerts a substantial inhibitory effect on replication of certain viruses (e.g., herpes simplex virus and respiratory syncytial virus) within primary target cells in vitro. To study the basis for its viral inhibitory activity, a suspension of 1-docosanol was formulated in an inert and nontoxic surfactant, Pluronic F-68; this suspension exerted potent inhibitory activity on the ability of susceptible viruses to infect cultured target cells. Susceptible viruses included wild-type herpes simplex viruses 1 and 2 as well as acyclovir-resistant herpes simplex virus 2 and also respiratory syncytial virus--all of which are lipid-enveloped. In contrast, nonenveloped poliovirus was not susceptible to the inhibitory action of 1-docosanol. Although the precise mechanism has yet to be defined, current evidence suggests that 1-docosanol inhibits viral replication by interfering with the early intracellular events surrounding viral entry into target cells. It is possible that interaction between the highly lipophilic compound and components of target cell membranes renders such target cells less susceptible to viral fusion and/or entry. If this mechanism proves to be correct, 1-docosanol may provide a broad spectrum activity against many different viruses, especially those with lipid-containing envelopes.

Affinity labeling of folate transport proteins with the N-hydroxysuccinimide ester of the gamma-isomer of fluorescein-methotrexate.

Fluorescein-methotrexate, a derivative in which the fluorophore is linked via a diaminopentane spacer to either the alpha- or gamma-carboxyl group of the glutamate moiety in the drug [Gapski et al. (1975) J. Med. Chem. 18, 526-528], has been synthesized by an improved procedure and separated by DEAE-Trisacryl chromatography into the alpha- and gamma-isomers (alpha-F-MTX and gamma-F-MTX). Each isomer was characterized by mass spectrometry, elemental analysis, absorbance spectrum, TLC, and reversed-phase HPLC. Identity of the isomers was established by the following enzymatic criteria: (a) gamma-F-MTX (but not the alpha-isomer) was hydrolyzed at the pteroate-glutamate bond by carboxypeptidase G2 to yield 4-amino-4-deoxy-10-methylpteroate and gamma-glutamyldiaminopentane-fluorescein; and (b) gamma-F-MTX was a much better inhibitor of human dihydrofolate reductase than the alpha-isomer (Ki values of 0.079 and 4.6 nM). alpha- and gamma-F-MTX were comparable as inhibitors (Ki values of 1.6 and 0.6 microM) of the transport system for reduced folates and MTX in L1210 cells, but the transporter in Lactobacillus casei was inhibited only by the gamma-isomer (Ki = 4.3 microM). The gamma-isomer, therefore, was selected for covalent labeling of proteins. When L. casei folate transport protein (18 kDa) was treated with gamma-F-MTX that had been activated with N-hydroxysuccinimide (NHS), the protein was readily visualized as a fluorescent band on SDS-PAGE electrophoretograms. The probe was also able to detect the transporter in membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Visualization of folate transport proteins by covalent labeling with fluorescein methotrexate.

Fluorescein-methotrexate (F-MTX) has been synthesized by an improved procedure and separated via chromatography on DEAE-Trisacryl into the alpha- and gamma-isomers. Purity of each isomer was verified by TLC, HPLC, and absorbance spectra. Identity of the alpha- and gamma-isomers was established by the following biological criteria: the gamma-isomer inhibited dihydrofolate reductase and was hydrolyzed by carboxypeptidase G2 (at the pteroate-glutamate linkage). The alpha-isomer, conversely, was unreactive in both systems, which is consistent with the specificity of these enzymes. Based upon these results, the gamma-isomer was selected for covalent labeling of proteins. Fluorescent bands were observed when the 22 kDa human dihydrofolate reductase and the 18 kDa folate transporter from Lactobacillus casei were treated with gamma-F-MTX (activated by N-hydroxysuccinimide) and subjected to SDS-PAGE. The probe was also useful for visualizing in situ the micromolar folate transport protein in L1210 cells.

Visualization of membrane-associated folate transport proteins.

Transport of Methotrexate (MTX) into cells, via the "reduced folate" transport system, is a critical factor in the effectiveness of the drug in cancer chemotherapy, and defective transport is one of the principal types of resistance to MTX. Probes capable of detecting membrane-associated folate transport proteins (ftp's) in individual cells are potentially useful for identifying structural and functional domains and for investigating mechanisms of substrate translocation. Polyclonal antibody to highly purified ftp from Lactobacillus casei, in conjunction with a second, gold-labeled antibody, has been used to visualize, via electron microscopy, the protein in Triton-treated membrane fragments and in the membrane and cytoplasm of spheroplasts. To visualize ftp in L1210 cells, the substrate-binding site was first labeled covalently with activated fluorescein-Methotrexate, and the cells were then treated with anti-fluorescein antibody and the gold-labeled antibody.

Antibody for detection and quantitation of membrane-associated folate-binding protein from Lactobacillus casei.

Lactobacillus casei cells contain a 25 kDa, membrane-associated, folate-binding protein (fbp), which is a component of the folate transport system. Polyclonal antibody to fbp (anti-fbp) has been prepared, and conditions have been established for detection and quantitation of the protein. Anti-fbp did not block [3H]folate transport or binding in L. casei cells. As judged by Western blots, the antibody reacted only with fbp on sodium dodecyl sulfate electrophoretograms of Triton X-100 extracts of L. casei membranes. Anti-fbp showed no cross-reactivity with L. casei dihydrofolate reductase, L. casei 5,10-methenyltetrahydrofolate synthetase, L1210 dihydrofolate reductase, rat liver dihydrofolate reductase, or L1210 folate-binding protein. Enzyme-linked immunosorbent assay measurements indicated the presence of an fbp in membranes of Lactobacillus salivarius and two transport-defective sublines of L. casei. Anti-fbp was used to demonstrate selective extraction, with n-butanol, of fbp from a mixture of Triton-solubilized L. casei membrane proteins; repression of fbp in membranes of L. casei cells grown on high levels of folate; and localization of fbp by electron microscopy, using anti-fbp in conjunction with goat anti-rabbit IgG gold conjugate, in L. casei membranes.

Tailored surface modification by ion implantation and laser treatment.

An important trend in materials science is the use of increasingly sophisticated methods to control composition and microstructure during processing. Near-surface modification by ion implantation and laser treatment is one of these new methods for tailoring material properties. Novel materials have been formed which are far from thermodynamic equilibrium and which exhibit unexpected and useful properties. The most extensively studied property changes include modified electrical properties of semiconductors and improved wear, hardness, and corrosion resistance of metals. The high degree of control available with energetic beams allows relations between microstructure and properties to be systematically investigated at the atomic level. This article illustrates how ion and laser beam modification is being applied to advance both the technology and the exploratory science of materials.

Secondary structure specificity of the nuclease activity of the 1,10-phenanthroline-copper complex.

The artificial DNase activity of the 1,10-phenanthroline-cuprous ion complex [(OP)2Cu+] and H2O2 cleaves the A, B, and Z forms of DNA at different rates. The B structure, formed by most DNAs including poly(dA-dT) and poly(dA) X poly(dT), is the most susceptible to cleavage. It is completely degraded within 1 min by 40 microM 1,10-phenanthroline/4 microM Cu2+/7 mM H2O2/7 mM 3-mercaptopropionic acid. The A structure, formed by RNA X DNA hybrids such as poly(rA) X poly(dT), is cleaved in both strands roughly 10-20% as rapidly as poly(dA-dT) under comparable conditions. In contrast, the left-handed Z structure, formed by poly(dG-dC) in 3.0 M NaCl, is completely resistant to cleavage even though the same copolymer in the B structure at 15 mM NaCl is readily degraded. Poly(dA-dT) is rendered acid soluble at both salt concentrations at similar rates. The basis for the secondary structure specificity of the DNA cleavage reaction most likely resides in the requisite formation of a productive complex between (OP)2Cu+ and DNA during the course of this reaction. Previous studies have suggested that strand scission is due to oxidative destruction of the deoxyribose by hydroxyl radicals produced by the oxidation of DNA-bound Cu+ by H2O2. Apparently, the Z and A structures are unable to form a stable noncovalent complex with the same optimal geometry for cleavage as the B structure and are less susceptible to degradation. This artificial DNase activity may provide an approach to assess the formation of non-B-DNA structures in solution.